4放十位有24个。43.012,43.021,43.102,43.120,43.201,43.21042.013,42.031,42.103,42.130,42.301,42.31041.023,41.032,41.203,41.230,41.302,41.32040.123,40.132,40.213,40.231,40.312,40.321注意写数时按一定规律写。同理可写出十位是3,2,1的各24个。所以共有24×4=96个三位小数。